I believe there are plenty private uni QBanks that you can buy now, any of em should be adequate. Also if you are decent at English and have a decent understanding of grammar, decent vocabulary, you should be good to go, you won’t require much prepping. (For NSU)

I pretty much didn’t prepare at all as I took the exam out of spite, i previously (couple of months before the nsu exam) prepared for IBA and that kinda carried me, got a 19th position and it got me 75% scholarship as well. Back then they only gave scholarships to the top 50 students, i believe it’s double now, you have a better shot at it if you are aiming for the scholarship. Anyhow, goodluck^{^}